Device at cooling baths for tempering furnaces

ABSTRACT

In a cooling bath arranged in connection to a tempering furnace, a shielded chamber being immersed in the bath, a smooth first conveyor running horizontally through said chamber, perforations in said conveyor being adjustable to coincide with corresponding perforations in the bottom of the chamber, reversible means for giving a cooling fluid contained in the bath an ever changing flow direction within said chamber, a second sloping conveyor provided with carrier means and adapted to bring the cooled work pieces up from the bath after passing the shielded chamber. By constantly changing the flow direction of the cooling fluid and by governing the rate of flow through the chamber by means of the adjustably arranged communications between the perforations in conveyor and chamber bottom it is possible to obtain a very uniform cooling.

11 3,744,776 July 10, I973 1 DEVICE AT COOLING BATl-IS FOR TEMPERINGFURNACES Bengt Johan Nyberg, Goteborg, Sweden SKF Industrial Trading andDevelopment Company N.V., Amsterdam, Netherlands Filed: Sept. 1, 1971Appl. No.: 176,978

lnventor:

Assignee:

US. Cl. 266/6 R, 148/144, 148/153, 266/4 A Int. Cl C2ld l/64 Field ofSearch 148/143, 144, 153; 266/4 A, 6 R, 6 S

References Cited UNITED STATES PATENTS 6/1943 Purnell 148/153 3,164,656l/1965 lpsen 266/6 R 3,340,109 9/1967 Keough 148/153 FOREIGN PATENTS ORAPPLICATIONS 53,325 5/1967 Poland 148/153 1,216,905 5/1966 Germany148/143 Primary Examiner-Gerald A. Dost Attorney- Dexter N. Shaw, EugeneE. Renz,Jr. et al.

[57] ABSTRACT In a cooling bath arranged in connection to a temperingfurnace, a shielded chamber being immersed in the bath, a smooth firstconveyor running horizontally through said chamber, perforations in saidconveyor being adjustable to coincide with corresponding perforations inthe bottom of the chamber, reversible means for giving a cooling fluidcontained in the bath an ever changing flow direction within saidchamber, a second sloping conveyor provided with carrier means andadapted to bring the cooled work pieces up from the bath after passingthe shielded chamber. By constantly changing the flow direction of thecooling fluid and by governing the rate of flow through the chamber bymeans of the adjustably arranged communications be tween theperforations in conveyor and chamber bottom it is possible to obtain avery uniform cooling.

3 Claims, 2 Drawing Figures PATENTEI] JUL 1 0 I975 DEVICE AT COOLINGBATHS FOR TEMPERING FURNACES BACKGROUND OF THE INVENTION Annular workpieces, e.g., such intended for parts of rolling bearings of differentkinds, are upon final machining tempered in such a manner that they areheated in a furnace and thereupon are conveyed through a cooling bath.

The normal manner in which this is carried out is that the work piecesare transferred from the furnace via a chute feeder to an endlessconveyer belt having a receiving portion in the bath and one portionwhich projects upwards out of this in order to deliver the cooled workpieces. The cooling liquid, the oil, is always kept in motion by aid offor instance one or more pumps, propeller devices or the like, which areimmersed in the bath.

It has, however, shown that the work pieces are somewhat deformed, dueto the one-sided directed oil flow, i.e., the cooling which they areexposed to. Due

This conicity may amount to 0.05 0.15 mm at rings having a diameter, of75 100 mm. Rings having nonsymmetrical material section, i.e., outerrings for taper roller bearings, will become more exposed to such errorswhen the thinwalled side of the ring arbitrarily is turned downwards.Rings having a nonsymmetrical material section in themselves have atendency of becoming conical, due to the fact that the forming ofmartensite takes place non-uniformly in the varying material section butthe error is increased if the thin portion is turned to a one-sideddirected cooling fluid flow. The non-uniform cooling furthermore causesa certain outof-roundness (ovality).

In order to be able to get the work pieces up from the bath, the beltgenerally is provided with carrier means. This, however, easily maycause that the work pieces are gathered already on the primary coolingportion of the belt which causes an impaired cooling of the separatework pieces with out-of-roundness as a result.

SUMMARY OF THE INVENTION The aim of the present invention is toeliminate the above-mentioned drawbacks, and this is effected therebythat the conveyor belt is adapted to pass through a shielded unit whichis immersed in the bath and in which the flow of the cooling fluid bymeans of suitably designed mechanical means is brought constantly tochange direction.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings attached there areshown an embodiment as an example suited for the cooling bath after afurnace for tempering rings for rolling bearings.

FIG. 1 is a section through the bath with a portion of the conveyorbelt; and

FIG. 2 is a cut along line 2-2 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The annular work pieces aretransferred from the tempering furnace 10 which is not shown in detail,through a chute feeder 11 to a cooling bath which is generally numbered12. This bath is formed as a large tank comprising a considerablequantity of cooling fluid. In thebath there is entirely immersed ashielded unit, the flush chamber 13, which principally is designed as abox provided with a horizontal throughpassage 14. In the bath there isarranged a conveyor belt 15 which runs over rollers 16 being arranged ina suitable way and being driven in a manner which is not further shown.The very belt is provided with holes or is perforated and extends with afirst receiving portion 17 in a horizontal direction through the passage14, outside this to the opening of the feeder 11. The conveyor belt 15comprises a rising portion 18 by aid of which the work pieces areconveyed up from the bath after the treatment is finished.

The wall portion 19 and 20 respectively of the flush chamber 13, whichare parallel with the receiving portion 17 of the belt are perforatedand adapted to cooperate with plates 21 and 22 which also are perforatedand which by means of a lever 23 may be moved in the plane of thewallportions in such a manner that the perforations in the wall portionsand the plates respectively may be brought to coincide more or less,thereby to govern the flow velocity of the fluid.

In the flush chamber 13 there are mounted two propellers 24 which aredriven by one motor 25 each. The propellers are provided with pivotableblades and by means of pneumatical maneuvering and a time relay theadjustment of the propeller blades may be changed at even timeintervals, i.e., each fifth second. The cooling fluid thereby is pressedthrough the passage and the belt at right angles against the directionof movement of this, alternately from the upper side and downwards andfrom the lower side and upwards, respectively.

The work pieces which pass down through the feeder l l'are distributedover the first portion of the conveyor belt and are slowly conveyedthrough the shielded unit. The work pieces thereby will be exposed to afluid flow which constantly changes direction and its temperature may bekept at a desirable value thereby that the flow path is settled in orderto eliminate the risk for conicity as far as possible.

A conveyor belt which is entirely smooth is not able to transfer thework pieces up from the bath and in order to prevent that,the workpieces are gathered by carrier members already in the first part of theconveyor belt, the very belt is designed without such carrier members.Parallel to the portion 18 of the conveyor belt 18 which-projects fromthe bath there is therefore arranged a second conveyor belt 26 which isprovided with carrier members 27 adapted to catch the work pieces at theend of the horizontal path 17 of the belt and which members carry thework pieces up along the rising portion 18.

Cooling fluid is lead vertically through the passage 14 upwards ordownwards respectively and, if so desired, it is of course possible toarrange adjustable openings in the outer walls of the flush chamber inorder to allow introduction and discharge respectively of cooling fluidto the interior of this. The number of propellers must be adapted to thecapacity of the cooling bath and other means for reversing the workingdirection of the propellers such as phase inverters at the motors canalso be used.

What I claim is:

l. A device at cooling baths for tempering furnaces intended fortreatment of preferably annular work pieces which from the furnace aretransferred to a conveyor belt being immersed in a cooling bath andthrough which belt a cooling fluid may be brought to flow, in which theconveyor belt is adapted to pass through a shielded unit, the flushchamber, which is immersed in the bath and in which the flow of thecooling fluid is brought constantly to change its direction by means ofsuitably designed mechanical means.

2. A device according to claim 1 in which the conveyor belt extendsthrough a horizontal passage in the flush chamber, wherein wall portionsof the passage being parallel with the belt are perforated and at leastthat one of these are adapted to cooperate with an also perforated platewhich is movable in the plane of the members.

Patent NO. I Dated l0,

Inventor(s) Bengt Johan Nyberg It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

On the cover sheet insert I30] Foreign Application Priority DataSeptember 2, 1970 Sweden 11905/70 Signed and sealed this 29th day ofJanuary 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents ORM PC4050 $59) 2 USCOMM-DC 60376-P69 UIS.GOVERNHENT PIJNTING OFFICE! O 3$-33. a

1. A device at cooling baths for tempering furnaces intended fortreatment of preferably annular work pieces which from the furnace aretransferred to a conveyor belt being immersed in a cooling bath andthrough which belt a cooling fluid may be brought to flow, in which theconveyor belt is adapted to pass through a shielded unit, the flushchamber, which is immersed in the bath and in which the flow of thecooling fluid is brought constantly to change its direction by means ofsuitably designed mechanical means.
 2. A device according to claim 1 inwhich the conveyor belt extends through a horizontal passage in theflush chamber, wherein wall portions of the passage being parallel withthe belt are perforated and at least that one of these are adapted tocooperate with an also perforated plate which is movable in the plane ofthe wall portions in order to adjust the area of flow.
 3. A deviceaccording to claim 1, wherein the conveyor belt is designed as a smoothbelt adapted to project up from the bath after the flush chamber andthat the rising portion of the conveyor belt is intended to cooperatewith a second conveyor belt which is arranged parallel with the firstone and is provided with carrier members.